System for transmitting intelligence



Aug. 4, l36. w. s. I EMMON v SYSTEM FOR TRANSMITTING INTELLIGENCE 2Sheets-Sheet 1 Filed March 2, 1955 INVENTOR. Wa/rer 62 Lemma/7.

@my 9L ,20%

' A TToRNEYS.

Aug. 4, 1936.

SYSTEM FOR TRANSMITTING INTELLIGENCE w. s. LEMMON Filed March 2, 1955 2sheets-sheet 2 IN V EN TOR. Wd/'f 5. Lem/7700.

A TTORNE YS.

practice to provide inthe sender a multiplicity oi of the sender.

Patented Aug'. V4, 1936,"

vUNrraD s'r-A-'rrlsl PATENT OFFICE v'waiter s. y., miglior, by

mesne assignments,

poration-of NewYork application March 2,

to International Business Machines Corporation, New York,

N. Y., a cor- 1935, serial No. asis 4 claims, '(01. 11s-s2) y 'I'hisinvention relates tothe transmission of intelligence either throughwired circuits or by radio, and more particularly to that vtype oftransmission wherein the signal impulsesvpro- 5 duced by the operationof a typewriter or like machine, are so timed in their transmission that-they may be picked up and differentiated on a time basis by thereceiver for causing the appropriate characters to be reproduced.

In systems of the kind referred to it is the circuits, each individualto a Vparticular charac ter, and each including a contact ysegment of acommutator, together with a rotary collector '15 adapted to engage eachcommutator segment at a predetermined point in its cycle of operations.The arrangement is such that an actuation of a key of the transmittingmachine causes the cir'- cuit individualto thatkey -to be charged and 20stored with electrical energy. When the rotary collector engages thecommutator segment included in that particular circuit a discharge takesplace causing current to now, and this discharge f is'inductivelytransmitted into the output circuit' The receiversimilarly 'includes aeceiving distributor which comprises a rotary rm or contact member and acommutator over w ch the rotary distributor arm runs. When the signalcomes through it is transmitted through the particular` commutatorcontact which is at that instant en-.v gaged by the rotary distributorand hence provduces an actuationof a signal. character key in thereceiving typewriter associated with the circuit of that particularcontact.

It is important in such a system thatthe sending collector and thereceiving distributor bev operated 'synchronously and in 'phase with oneanother', and lto this end it is desirable that the motors for operatingthem be alike and that the operatingcurrent supplied to the motors beexe actly the same in character. It isaccordingly afeature ofthe presentinvention to utilize' the vordinary alternating line current such as the60 cycle current-commonly supplied by electric light and power companiesor ob-l Y tained from local generators for operating the motor of thetransmitting collector, and at 'the same time to transmit a portion ofsaid current with the signal impulse to the receiver and there -todetect andl amplify this alternating current component for driving themotor of the receiving Y distributor.

It is a further feature of the invention to pro- 55 vide suitableiiltering and amplifying means in a one terminal of one of the contactwith branch circuit of the Ireceiver for amplifying th signal impulsesand transmitting them to the writing instrumentalities while suppressingthe arnating current component in the branch circ Other objects andadvantages will hereinafter appear.

In the drawings cation,

Figure 1 isa diagrammatic View illustrating the transmitting andreceiving apparatus of the system, and

Figure 2 is a certain features of thev tail than Figure 1.

An alternating current generator I supplies alternating current throughline conductors 2 and forming part of thisl specidiagrammatic viewillustrating transmitter in greater de- 3, andthence through a suitableswitch 4, to a circuit comprising a conductor 5, a primary transformercoilI, and a conductor rl. Branch conductors 8 and 9 are connected tothe conduc- -tors 5 and 1, respectively, and run to the terminals ofamotor III which, through its output shaft II, drives a determinedspeed.

of 'a stationary commutator I6. The conductor I3 -is vconnected to aprimary transformer coil I1 and the coil Il in turn is connected to aconductor I8. The conductor throughya multiplicity of 'parallel wires I9to condensers 20 each of the wires I 9 running to condensers. Theopposite terminal oi each condenser 20 is connected through a switch arm2| ,which is normally in contact with a conductor 22 running to vone ofthe segments I4 ofthe commutator I6. The condensers are normallydischarged and hence the circuits which are successively completedthrough the condensers by the running of the distributor arm I 2 uponthe contacts I4 are dead circuits eircept when' one of them has beenener- EachA condenser is adapted to be charged by the actuation of aparticular type key or other operating instrumentality of Vthetransmitting typewriter 23. When a key of the 'typewriter is depressedone of the switches 2I (associated exclusiveiy with that key) ismoved-away. from the terminal of the associated conductor 22 and intothe terminal of an associated conductor 24. This closesa circuit forcharging the condenser 20 individual to thaty switch, such cirrotarycollector'arm I2 at pre-t I8 is connected automatically by a spring,into engagement with the terminal of the;l associated conductor' 22. Themomentary engagementof Athe switch with the conductor 24 iseective tocharge the associated condenser but the condenser eannotxbe dischargeduntil the distributor arm l2 wipes.

across the segment or contact I4 which is in circuit with thatparticular condenser. vWhen this occurs the condenserl is discharged anda.v signal impulse lscaused to iiow through the primary winding I1. i

'A The alternating line current flowing through` the primary winding isinductively transmitted' finto a secondary` circuit 28 through a.secondary winding 29, and the signal impulses which flow through theprimary winding I1 are inductively transmitted vinto thel secondarycircuit through a secondary winding 30. The current thus in- .duced inthe secondary circuit is fed-into a modulator 3l yand is there impressedupon a'carrier current generated by an oscillator 82 and broadcast froman antenna 33.

vIn order to guard against inductive transmission of the alternatinglinecurrent ,into the cirv cuits of the condensers 26 through the coils 30and I1 as primary and secondary, respectively, provision is, desirablymade ofi-'a resonant shunt circuit 34 between the conductorsV I 3 andI8, said circuit comprising an inductance 85 and a condenser 36, whosecharacteristics'are such that vthe shunt circuit will short circuit anyalternating current voi' line frequency present; l i

y In addition to the alternating line current andA the signal impulseswhich are transmitted, itis desirableftha't a phase control impulse betrans-k mitted at a. predetermined pointV in each cycle' which may beand tothis end the commutator contact I5 is,V i

provided. 'A conductor 31 connects the conductor 21 andhence the batteryto contact I5. It

will seem that each time the arm I2 engages the contact I5` acircuitisclosed through the battery --and the primary coil I1 causing a.phase control impulse to. be transmitted. This occurso'nce in e eachrevolution', and at a predetermined point.

The receiver comprises an aerial 98 and a" groundv 39 forming parts ofa-,radio receiving set i 40 of conventionaldesign. In this receiving.'set the received energy'may beampliiied. and the currentof Ylinefrequency aswell 'as the signal and phase control impulse maybedetected. The

output circuit 4I of the receiving setv 40 includes a.4 primary winding42 which is'inductivelyl `coupled to secondary windings 43 and 44 ofseparate circuits45 and 46. The circuit 45 is a motor operatingcircuitandds supplied Y with 1 received and amplled alternating \currentimpulses identical in character with the alternating current impulseswhichl drive themotor I 9 oi the transmitter. This currentin the circuit45 is used to drive a-motor 41 which, throughits-output shaft 46, drivesthereceivin'g distributor 49 and phase control contact arm 50. The motor41 is exactly likethe motor I0, and since the current supplied 'plienshaft 48 through diii'erential mechanism `(not Ishown) and each timethat the 'electromagnet toboth motors is identical in character thetendency of .the two motors is to operate identically as to speed. l

I Thecircuit 46 -is designed to segregate the signal and controlimpulses from the alternating current and to amplify them and transmitthem f to the receiving typewriter.` To this end the circuit includes afilter 5I to suppress. current of the known frequency of thealternatingcurrent received, and an amplier 52.y A conductor 53 `connects theamplifier .with the inner ends f-the armsjS-and 50. The arm 49 runs inengagement with contact segments 54 of a stationary com- I mutator 55and each contact segment 54 is connected through a conductor 56 tooperate a particulartypeharor other operating instrumentality of thereceiving typewriter. After passing through vthe receiving typewriterthe current fromallA of these conductors56 passes back .to

the' amplier through a conductor 51. The operating `and phase controlimpulsesv are all iden- `tical `in character, and are distinguished from,one another solely by the period in the cycle of lthe sender duringwhich theya're respectively transmitted. It is necessary, therefore, tomakeprovision for securing and maintaining phase,

correspondence between the sender and distribumentality of v`thereceiving typewriter which it is intended tor operate; To this endprovision is made of phase'control means of the same kind asillusrated'in my pending application `Serial No. 684,362, iiled Augustl9th, 1933, for Synchro-A nizing system.

This mechanism may be 'described briefly as follows: The conductor 53,as has been mentioned, is always connected to the inner end of A armv 50and to the inner cnd' of arm 49. The phase control impulse, transmittedwhenever the .arm I2 of the transmitter engages contact I5,

occursoncein each cycle and at the same. point in Yeach cycle. When thesender'and receiver A- tor in order to cause a received impulse toopcrate the particular type bar or other instruare'ilrst coupled theywill presumably be out of phase correspondence. N'o signalling impulsesare ktransmitted until a suiiicient interval has elapsed to permit phasecorrespondence to be secured. The arm 50 runs upon a ringvsegment 58 andcontacts 59, 60, and 6|. If the first signal impulse is transmittedthrough the ring 58 it is caused to pass vthrough a conductor 62, ayswitcharm 63, a conductor 64,-a conductor 65, an

advancing-electromagnet 66, and a conductor 61, tothe conductor 51 whichruns back to the am- The arms' 49 and 50 are driven-from' the ,66 isenergized it operates a pawl and ratchet device for advancing the varms49 .and 50 one contact space of the commutator`55` relative to the shaft48. As the operation contin es one of these adjusting steps will beapplied in each revolution untilv the arm 56 hasadvanced to a pointwhere it will no longerengage the contact ring 58 at the moment otreception of the control impulse but will engage the contact 6I. Thcurrent now flows throughthe contact 6I and conductor 65 to theadvancing electromagnet,

so that the next impulse will be received through the contact 60, thelcondition desired.

'The current now flows from theeconta'ct 60 4through a conductor 68, an'electromagnet 69, and a conductor 10" to the conductor 61. The switch 63constitutes the armature of. the electromagnet 69 and it is pulled away`from, engagecuited, and ineiective.

ready for the transmission of signal impulsesstore' pasecorrespondence.-

the ot er hand has advanced away from .phase ment with the terminal ofconductor 82 when the electromagnet 69 is energized to open-circuit thering segment 58. A retarding device 10, which may be a dashpot, isconnected to the switch 63 to cause it to act slowly so that the switch63 does no t return to engagement with the terminal of conductor 62 fora plurality of cycles of the arm 50. The control impulses should nowcontinue to come in on the contact 60, which produces no adjusting step,and the ring segment 58 is held continuously open cir- The. apparatus isnow since the transmission of signal impulses cannot now result in theproduction of adjusting' Should a condition occur tending to disturb thesynchronous and in-phase relation of the arm with reference to the arml2 of the transmitter, an adjusting step will immediately occur eitherin an advancing orretarding direction to restore phase correspondence.If the arm 50 has lagged the control impulse will be again transmittedthrough the contact 6i and an advancing step will immediately be appliedto re- If the arm 50 on correspondence the control impulse will passthrough the contact 59 thence through a conductor 1I, a retardingelectromagnet 12, and con.

ductor 13 to conductor 61. This will immediately apply a backwardadjusting step to restore phase correspondence. Switch 63 acts Aslowlyenough to permit these momentary deviations without permitting theswitch 63 to be closed.

I have described what I believe to be the best embodiments of myinvention. I do not wish, however, to be confined to the embodimentsshown, but what I desire to cover by Letters Patent is setforth in theappended claims.

I claimr- 1. In la system for transmitting intelligence, in combination,a sender comprising a sending machine having a keyboard, each key beingadapted when operated to cause the transmission of a signal impulse,means comprising a rotary collector and a commutator for alloting toeach key a definite period in the cycle of rotation, means in the senderfor initiating a phase control impulse ata predetermined point in eachcycle. a motor for driving the collector at uniform speed, a source ofalternating current, means connecting said source to drive the motor, anoutput circuit means for transmitting the alternating current and thesignal and control impulses into the output circuit, and a receivercomprising electrical receiving and amplifying equipment, a receivingmachine comprising printing instrumentalities, a commutator and a rotarydistributor for causing the received signal impulses to operate theprinting instrumentalities selectively in accordance with the timing ofthe received signal impulse, a motor for operating the distributor,means for transmitting the received and amplified alternating current tooperate the receiver motor, and means for transmitting the receivedsignal impulse exclusive of the alternating current, through thedistributorto the several printing instrumentalities, and meansresponsive to the reception of the control im- `pulse in all positionsof the distributor other than that representing phase correspondence forautomatically applying one or more adjusting steps to the receivingdistributor for stepping the same into phase correspondence with thesending collector.

2. In a systemyfor vtransmitting intelligence, in combination, a sendercomprising a sending machine having a keyboard, each key K being adaptedwhen operated to cause the transmission of a signal impulse,means'comprising a rotary collector anda commutator for allotng to eachmeans in the sender for initiating a phase control impulse at apredetermined point in each cycle, a motor for driving the collector atuniform speed, a sourceof alternating current. means connecting saidsource to drive the motor,

key a definite period in-'the cycle of rotation, 20

an output circuit, means for transmitting the 1 of the received signalimpulse, 'a' motor for operl ating the distributor, means fortransmitting the received and amplified alternating current to operatethe receiver motor, and means for transmitting the received signalimpulse exclusive of the alternating current, through the distributor tothe several printing intrumentalities, and A means responsive to thereception of the control impulse in all positions ofthe distributorother than that representing phase correspondence for automaticallyapplying lone or more adjusting steps to the receiving distributor forstepping the same into phase correspondence with the Vsending collector,and for automatically correcting the phase adjustment withoutinterrupting the reception of signal impulses.

3. The invention set the means, for transmitting the alternating currentand signal and control impulses comprises inductive means.

4. The invention set forth in claim 1 in which the means fortransmitting the received signal impulse exclusive of the alternatingcurrent through the distributor comprises a transmitting circuit4 havinga filter incorporated therein for iiltering out current of the knownfrequency .of the motor operating current.

WALTER. s. Lemmon.

forth in claim 1 in which

